MAYBE
63.04/23.66	MAYBE
63.04/23.66	
63.04/23.66	Problem:
63.04/23.66	 a(a(b(b(x1)))) -> a(b(a(a(x1))))
63.04/23.66	 a(x1) -> b(b(b(x1)))
63.04/23.66	
63.04/23.66	Proof:
63.04/23.66	 Open
63.04/23.66	EOF